BRCA1 and breast cancer: Having established that BRCA1 positively regulates FOXO3 expression through inhibiting the ability of EZH2 to mediate FOXO3 methylation and silencing in human breast cancer cells, we next examined the association between FOXO3 methylation and BRCA1 mutation status in a methylated DNA immunoprecipitation data set from familial breast tumour samples collected by kConFab (The Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer, Melbourne, Australia).27 There are 33 samples in the cohort, 11 of which harbour the BRCA1 mutation.